Vehicle Inverter Capacitor Module Ground Bus Bar Noise Reduction
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Solution Overview
Problem
In hybrid vehicle inverter-motor systems, existing capacitor modules fail to effectively minimize AM band common mode conduction noise and parasitic components, leading to noise and resonance issues during motor operation.
Innovation Solution
A capacitor module for vehicles that connects Y-capacitors in parallel with a DC high voltage input terminal, with each Y-capacitor having capacitor elements between high voltage input terminals and ground bus bars, ensuring balanced paths to minimize parasitic parameters and resonance, and optimizing the arrangement of ground bus bars and capacitor elements to reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If Y-capacitors are connected in parallel to the inverter input, then common mode noise is reduced, but parasitic components and resonance issues occur due to unoptimized current paths
Solution Approach 1:
The patent applies local quality by making each Y-capacitor's current path unique and optimized for its specific function. Each capacitor has its own dedicated current path with minimized parasitic inductance, allowing each component to operate at its optimal performance point rather than sharing a common compromised path.
Solution Approach 2:
The patent segments the grounding system by providing separate ground bus bars for each Y-capacitor instead of using a common ground connection. This segmentation prevents ground loops and ensures that each capacitor's noise filtering action is independent and effective, eliminating the parasitic coupling that would occur with shared grounding.
2Object-affected harmful factors
If multiple Y-capacitors are used to enhance noise reduction, then filtering capability increases, but resonance effects are amplified due to unbalanced parasitic parameters
Solution Approach 1:
Each Y-capacitor is designed with locally optimized current paths that minimize its individual parasitic inductance. The separate ground bus bars ensure that each capacitor operates with its own optimized electrical characteristics, preventing the parasitic parameter mismatches that would cause resonance when multiple capacitors are used together.
3Object-generated harmful factors
If capacitor elements are arranged to minimize path length, then parasitic inductance is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple current paths into a single integrated capacitor module structure. By combining all Y-capacitors and their individual current paths into one pre-assembled module with built-in separate ground bus bars, the design achieves minimized parasitic inductance while simplifying manufacturing and installation at the system level.
Data Source
AI summary
A capacitor module of an inverter for a vehicle includes: a DC-link capacitor configured to be connected in parallel to an input of an inverter between a first high voltage input terminal and a second high voltage input terminal; and a plurality of Y-capacitors configured to be connected in parallel to the inverter. Each of the plurality Y-capacitors includes a first capacitor element connected between the first high voltage input terminal and a ground bus bar and a second capacitor element connected between the second high voltage input terminal and the ground bus bar, and the ground bus bars of the plurality of Y-capacitors are separately provided and the ground holes of the ground bus bars are disposed so as to face each other in a first direction.